After eight years of pitching and persuading, the first New York Television Festival opened Wednesday with the backing of TV Guide, such networks as NBC, Fox, MTV and Comedy Central, and powerhouse agencies like William Morris. Participants are an eclectic lot that includes a former NASCAR racer and a metalworker in Madison, Wis. Most found out about the event online or at one of three launch parties in New York, Los Angeles and London earlier this year. As the first event of its kind, the television festival represents an initial step toward creating an alternative way to develop programming outside the studio and network system.